Fiber lasers are reliable and flexible sources of high laser power with excellent beam quality. However, limitations due to nonlinear and thermal effects, hamper further power scaling. We will give an overview over relevant influencing factors for these limitations, on the component side as well as regarding system design. Experimental examples in the 1µm and 2µm spectral region will be shown for the proposed techniques to tackle several of these obstructions, with a focus on ways to suppress transverse mode instabilities.
Remaining limitations for single fiber systems can be overcome by parallelization of amplification, using multiple actively doped cores running below the critically power threshold each. Such fiber cores can be housed separately or in a single multi-core fiber. We will address coherent and spectral methods to (re-)combine multiple fiber laser output beams while maintaining beam quality and discuss scaling aspects and potential limitations to these architectures.
Spectral Beam Combining (SBC) is a useful tool for power scaling of optical systems as well as for multiplexing in communications. We will give an overview of different concepts for SBC and compare them regarding channel count, spectral properties and power handling. For this regard, we will present our examples of these concepts, ranging from a 20kW spectral combiner for high power application over systems in the 100W-range for free-space communications in different spectral regions down to miniaturized combiner concepts for multi-W applications to reduce the footprint.
Dense wavelength division multiplexing techniques are widely used in terrestrial state-of-the-art telecom applications. The optical link between the terminals requires a data rate in the terabyte range which is typically realized by transmitting multiple wavelengths though one common channel. For satellite communications, completely new requirements and demands arise where the common technologies cannot be used without further ado. In space, it is also completely impractical to set up repeaters at short distances, so the WDM must have a capacity of tens of Watts power capability to cover the very long propagation length. The development and realization of a space-suitable Dense Wavelength Division Multiplexer and Demultiplexer are described. Both units combine (or split, respectively) ten channels into / from one common channel. The design central wavelength is around 1070 nm and the channels are chosen with a separation of 92-GHz corresponding to approximately 0.35 nm. The multiplexer has a target power handling of at least five Watts per channel. The input channels are equipped with PM fibers, whereas the multiplexed output is free space propagating, avoiding nonlinear effects and thermally induced fiber damage. The Demultiplexer is fiber coupled at input and output ports due to the reduced power requirements of sub Milliwatts. In both cases a diffraction grating is used as wavelength selective element. Its nonlinear angular dispersion is compensated with a non-equidistant fiber arrangement. The WDMs are characterized regarding optical parameters. The components are designed for space suitability, using appropriate materials and thermal design.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.